(a) Field of the Invention
This invention relates to 1,2-dihydro-5-(pyridinyl)-2-oxonicotinamide derivatives, their preparation, their cardiotonic use and their conversion to the corresponding 3-amino-5-(pyridinyl)-2(1H)-pyridinones, also cardiotonics.
(b) Description of the Prior Art
Lesher and Opalka U.S. Pat. Nos. 4,004,012, issued Jan. 18, 1977, and 4,072,746, issued Feb. 7, 1978, show as cardiotonic agents 3-amino-5-(pyridinyl)-2(1H)-pyridinones and their preparation from the corresponding 3-carbamyl compounds. Said 3-carbamyl-5-(pyridinyl)-2(1H)-pyridinones, alternatively named 1,2-dihydro-2-oxo-5-(pyridinyl)nicotinamides, were shown only as intermediates.